It is generally recognized that the cells which comprise the heart muscle in mammals are post-mitotic. This leads to difficulties in injured or diseased heart muscles, which are largely unable to repair damaged cells that become necrotic. After such damage, the efficiency and output of the heart muscle are decreased, placing additional stress on the heart, leading to further damage and necrosis, and ultimately to heart failure.
The downward spiral from healthy heart to failing heart can result from a number of conditions including physical injury, heart disease, including congenital heart disease, and infections of the heart or circulatory tissue. Diseases of the heart and circulatory system are often ultimately fatal, particularly conditions which result in heart failure, for example cardiomyopathies. At present there is no cure for most such conditions and many patients require, for example, ventricular assist devices and eventually heart transplants.
Presently, there is interest in using either stem cells, which can divide and differentiate, or muscles cells from other sources, including smooth and skeletal muscles cells, to assist the heart to repair or reverse tissue damage, restore function, or to at least halt the damage cycle leading to further loss of healthy heart tissue. In addition many circulatory diseases and injuries involve chronic or acute damage to, or necrosis of, circulatory tissues, and the cells of which such tissues are comprised. Cell-based and cell-derived therapies are of interest for these conditions.
There is thus a need in the art for cell-based, or cell-derived therapies which can aid in healing damaged heart or circulatory tissues, or which can result in the repair or replacement of such damage in a patient.